Los Alamos County, NM Property Tax: $2,591/yr (2026)
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The effective property tax rate in Los Alamos County is 0.57% of assessed home value. On a home at the county median value of $452,500, that works out to about $2,579 per year, or $215 per month. Los Alamos County is located in northern New Mexico, and is home to approximately 19,374 residents.
About Los Alamos County
Los Alamos County covers approximately 109.1 square miles in New Mexico. The county is home to about 19,374 residents living in roughly 8,660 housing units, of which 70.7% are owner-occupied. The median household income is $143,188, and the median home was built in 1974.
Los Alamos County borders Rio Arriba County, Sandoval County, Santa Fe County — useful comparisons if you're considering nearby areas with potentially different tax rates.
How Property Taxes Work in New Mexico
Property taxes in New Mexico are administered at the county level. Each county sets a millage rate applied to the assessed value of real property — the effective rate above accounts for any partial assessments and exemptions already built into the local tax base. Assessed value can differ meaningfully from current market value depending on how often the county reassesses and what fraction of market value it uses.
Most counties in New Mexico offer exemptions that reduce the taxable assessed value: homestead exemptions for primary residences, senior exemptions, disability exemptions, and veteran exemptions are common. These reduce your effective rate below the county-wide average shown here. Contact the Los Alamos County Assessor's office to learn which exemptions apply to your property and when to file.
Los Alamos County vs. Neighboring Counties
| Location | Eff. Rate | Median Home | Annual Tax |
|---|---|---|---|
| Los Alamos County, NM | 0.57% | $452,500 | $2,579 |
| New Mexico state average | 0.60% | — | $2,715* |
| Rio Arriba County | 0.43% | $230,900 | $1,000 |
| Sandoval County | 0.76% | $282,300 | $2,147 |
| Santa Fe County | 0.51% | $416,900 | $2,110 |
| US national average | 1.10% | $281,900 | $3,101 |
*State average annual tax computed at Los Alamos County's median home value of $452,500. Source: US Census ACS 2023 5-year estimates.
Frequently Asked Questions
How does Los Alamos County's property tax rate compare to the rest of New Mexico?
At 0.57%, Los Alamos County is lower than the New Mexico state average of 0.60%. On a home at the county median of $452,500, that means about $2,579 per year — versus $2,715 at the state average rate, a difference of $136 per year. Compared to the national average of 1.10%, Los Alamos County is below average.
What's a typical annual property tax bill in Los Alamos County?
For a home at the county median value of $452,500, the annual property tax in Los Alamos County is approximately $2,579 — or about $215 per month. For a home worth $678,750, expect around $3,869 per year. For a $905,000 home, approximately $5,159 per year. Use the calculator above to estimate taxes for any assessed value.
Where do I appeal a Los Alamos County property tax assessment?
Property assessment appeals in Los Alamos County are handled by the Los Alamos County Assessor's office. Most jurisdictions require filing within 30–90 days of receiving your assessment notice — confirm the specific deadline with the assessor's office before submitting, as deadlines and procedures vary by county. A successful appeal can reduce your assessed value and lower your tax bill for the current and future tax years.
What exemptions are available in Los Alamos County?
New Mexico counties commonly offer homestead exemptions for owner-occupied primary residences, senior citizen exemptions for qualifying homeowners aged 65 and older, exemptions for disabled residents, and veterans' exemptions. Each exemption reduces your assessed taxable value, which in turn reduces your effective tax rate below the county-wide 0.57% shown here. Contact the Los Alamos County Assessor's office to confirm which exemptions are available and the application deadlines.
Data sources: US Census Bureau ACS 2023 5-Year Estimates, US Census Gazetteer (2024), County Adjacency File